1. Field of the Invention
This invention relates to an optical system connection structure which optically connects an optical fiber inserted into a ferrule and an optical component, and to an optical communication module which connects a module converting an electrical signal to an optical signal and a module converting an optical signal to an electrical signal, and which transmits and receives an optical signal therein.
2. Description of the Related Art
In recent years, an optical interconnection has been broadly applied, which is a technology to transmit a signal at fast speed between an inside of a system apparatus and an apparatus or between optical modules. That is, the optical interconnection is a technology to treat an optical component as an electrical component, and to mount the optical component on a motherboard or a circuit substrate which is used, for example, for a personal computer, vehicle, and optical transceiver.
To increase a speed of a network signal, an optical communication module which is used for such an optical interconnection, uses an internal connection of a media converter or switching hub, an optical transceiver which transmits an Ethernet® signal having a gigabit class of transmission speed in a short distance, an inside of an apparatus (e.g., medical equipment, testing equipment, video system, and high-speed computer cluster), and a connection of components between apparatuses.
Accordingly, downsizing and lower cost are required for an optical communication module used in an infiniband which is a standard of a high-speed interface for a server, and research and development have been done so as to achieve such requirements.
A conventional optical communication module 111 as shown in FIG. 11 includes a photoelectric conversion module 113 disposed on a printed circuit board 112, an optical fiber cable connector portion 114 formed on an end of the photoelectric conversion module 113, and a housing 115 containing them. An electrical plug 116 is disposed at an end of the housing 115. The optical communication module 111 is used by connecting an optical fiber cable to the optical fiber cable connector portion 114.
The related arts of the invention are, for example, JP-A-2004-355894, and JP-A-2006-309113.
However, the conventional optical communication module 111 converts positive or negative (polarity) electrical signals having the same intensity, to optical signals, and transmits the optical signals to an optical fiber cable as an optical transmission line, or receives an optical signal from the optical fiber cable.
That is, the conventional optical communication module 111 either transmits or receives with respect to a single optical fiber. Therefore, when the optical communication module 111 is used in an infiniband which, as mentioned above, is a standard of a high-speed interface for a server, there are a lot of problems such that an entire module size increases, the number of components increases, and a price thereof increases.
In recent optical communication modules, a bi-directional communication type has become required, which can both transmit and receive by a single optical fiber at the same time. However, there has not been a product which achieves downsizing and yet keeps a high-speed transmission rate regardless of a multi-core fiber or a single-core fiber.
Further, although such optical communication modules generally include an optical system connection structure in which a ferrule connected to an optical fiber and an optical component are optically connected, a conventional optical system connection structure is difficult to collectively connect to a multi-core fiber.